Hydraulic fluid control panel



Feb. 23, 1954 o. MUELLER HYDRAULIC FLUID CONTROL PANEL Filed April 10,1950 4 Sheets-Sheet l #my NNT 4 Sheefs-Sheet 2 O. MUELLER HYDRAULICFLUID CONTROL PANEL Feb. 23, 1954 Filed April 1o, 195o Feb. 23, 1954 o.Mux-:LLER 2,669,841

HYDRAULIC FLUID CONTROL PANEL INVENTOR:` @Z720 /W'aeZZc/r Feb. 23, 1954O, MUELLER 2,669,841

HYDRAULIC FLUID CONTROL PANEL Filed April l0, 1950 4 Sheets-Sheet 4Patented Feb. 23, 1954 UNITED STATES `PATEN T OFFICE 2,669,841 HYDRAULIC"FLUID CONTROL PANL Otto Mueller, Dearborn, Mich. Application April 10,1950,.seriaiNdiMos 20 Claims. l

This linvention relates to apparatus for delivering hydraulic iluid at aplurality of pressuresand particularly to a power unit for deliveringlow and high pressure uids from a single low pressure pump withoutemploying high pressure valves.

Heretofore, apparatus for producing hydraulic power at a plurality ofpressures has usually been engineered and constructed more or less on aspecial unit and power plant basis. By this is meant that it has beencustomary for a factory requiring such apparatus. to build a single,perhaps centrally located and permanently installed. hydraulic pressureunit or plant to be used throughout the entire factory for supplyinghydraulic iluid at diilerent pressures to various apparatus. Whenbuilding individual units, separate motors and pumps were also employedto produce hydraulic fluid at low and hie-h preseures. In these types ofinstallations, high pressure operated Valves were required to change'from the diierent pressures these were expensive, leaked and werealways a source of trouble.

The present invention embodies the construction of a relatively small,emoient Aand inexpensive unit for producing hydraulic power. Such a unitYcan be purchased when it is needed and placed where it is to beoperated. It can be operated. when it is needed,` and it can be mor/edfrom one 4place to another `in the factory when conditions require suchmovement, crit can be disposed of or replaced when it, is not needed orwhen better or different equipment isboth ,cle-sir able and available.A. factory can. have few or manyV of these units, depending upon theneeds of the factory. and these can. be placed Where the work should cedone or near enough `thereto so that an extensive and factory-wideconduit sys tem is not requires. units can be separately controlled 'andeures may be made available in a factory so as to betterl suit the manyand .various needs that do arise.

An object of the invention is to provide a small, inexpensive; flexibleand efcient. hydraulic power unit "capable of d .ivering fluid under lowand high pressures.

Another object of the invention is to provide relatively small butiierible units for the productionoi hydraulic power pressure from a lowpressure pump and booster in such an arrangement as to avoid thenecessity of employing bleh pressure valves.

Another object of the invention is to provide a hydraulic power-unitcapable of delivering hydrauiic power oriiuid at several differentpres-` different iluid pres.-

`"2 eures, includingwhat might be considered extremelylhigh pressures,andthis withoutthe necessity ol using' a` control system for cutting.`on `'and off, various control valves operating at such high pressures.

Another object of 'the-invention is toprcvide a self-contained powerunit including a tank prolvidng asuppl'y and return chamber for thev-uidand a base forminga-support for elements of the unit;

A further object "of theinvention is to provide a hydraulic power unitthat can be installed and used in the vicinity of piercing,Weldingriveting or other machines or apparatus it-is employedto operate.

Other objects and features of noveltyof the'in- Vention will bespecically pointed out or Willbe- Icome apparentwheh referring, for avbetter understanding-of the invention, to the following description`taken in conjunction with the accompanying drawings, wherein:

Figure l is a side elevational view of a hydraulic power 'supplying unitembracing the principles of the invention;

Fig. y2 is a plan view Fig. 1; l

Fig. 3 is an end elevationall view of the structuresshown by Figs. l andA2;

Fig. 4 is a diagrammatical illustration or a power unit similar to lthatillustrated in Figs. l, 2 and 3, and

Fig. 5 is a diagramm-atical illustration of an electricalcontrolesysteem `which may be employed in controlling 'the operationof apower unit e1nbracing the principle of the invention as disclosed bythepreceding figures. i

Referring particularly to Figs.` 1,2 and 3, there is` indicatedgenerallyby the numeral Hl a relatively portable ,power' unit embracing the`prnciples ofthe invention. The unit lllcan be constructed `in varioussizes and capacities and can be employed for vsupplying hydraulic powerat various pressures foroperating machines, pistons or cylinders ofmachines employed in piercing,

of the lstructure shown by welding, riveting, clamping or holdingmetallic or other parts and subassemblies employed in manufacturingoperations where high production, low cost and Ilexibility of operationsare desirable, and for providing pressure duid for any other requirementincludig injection molding. By way of illustration, an application ofthe'structure disclosed in Figs. 1, 2 and 3 and indicated by the numerallll, appears in Fig. e, wherein the elements of the unit are illustratedas operating .a plurality o'f work-performing cylinders I I* which larebeing utilized for purposes to be hereinafter described. Other examplesof work-performinet elements in the operation of which a power unit suchas that illustrated by the numeral iii may be employed, are disclosed inapplicants United States Patent No. 2,353,488, issued July 1l, 1944, andNo. 2,534,292, issued December Y19, 1950 and copending application forLetters Patent, Serial No. 767,963, iiled August l1, 1947, now PatentNo. 2,586,695, issued February 19, 1952.

Referring particularly to Figs. l to 4, the power unit I comprises arelatively flat and preferably rectangularly shaped supply and returni'luid tank I2 which is adapted also to provide a movable base orsupport for the other elements of which the power unit also is composed.The upper horizontal wall of the tank I2 has secured thereto a motor I3having a drive shaft, the ends I4 and I5 of which project outwardly atopposite ends for driving pumps II and I8, respectively, through exiblecouplings I9. The pump II has an inlet connection to the tank i2 througha conduit and a strainer indicated at 2I and 22, respectively, and hasan outlet or supply conduit 23 for delivering pilot or relatively lowpressure fluid to the other units or elements of the system.

The pump Ii, or pilot iiuid producing and delivering element of thesystem, consists of a single pumping unit or element capable ofdelivering pilot fluid required for the operation oi certain of theelements of the power unit I Il, disclosed in the drawings, and for useto actuate units of the work-performing machine. The pump I8 comprises aplurality of pumping units, indicated at 24 and 25, these being employed`for the purpose of delivering the amount or volume of primary fluidrequired by the pumping unit ID to supply the demand for primary uid foroperating the work-performing elements to which the system is connected.The pumping units 24 and 25 have inlet conduits 2'! and 28 and strainers25 and 3! respectively, for supplying fluid thereto from the tank I2,and outlet or supply conduits 52 for delivering primary fluid from theunits of the pump I8 to the other elcments of the unit I!) for actuatingunits of the work-performing machine.

To insure the delivery of pilot and primary iiuids by the pumps Ii andI5, respectively, at relatively constant pressures and regardless of thedemand upon the system for such iiuids, the supply conduits 23 and 32from the pumps referred to are connected to pressure-regulating valves33 and 34, respectively, these valves being connected to a returnconduit indicated at 35 for returning iiuid not required` for theoperation of the system to the supply and return tank i2. The returnconduit 35 has a water-cooled fluid cooler 3'! inserted therein, inwhich cooler 3'! the circulation of water or other cooling liquid iscontrolled. by a temperature regulated ow control valve, indicated at 38in Figs. l and 2. A fluid cooler, such as that indicated by the numeral31' and which may be employed in the structure disclosed, is known inthe trade as Ross Cooler #'7-M-603AA. The regulator valve 35, such asPowers Regulator #11, should be set to produce a iiow of cold watersuicient to maintain recommended operating temperatures.

A by-pass conduit, indicated at 39, is employed in the return conduitSli and around the fluid cooler 3l. This by-pass is controlled by aspring loaded valve, indicated at 4I, which may be set in such a way asto permit the flow ci oil to the tank i2 through the by-pass 3Q in theevent the pressure within the conduit in the cooler 31 ex- 4 ceeds apredetermined maximum value. The pressure regulating valves 33 and 34are provided with adjustable pressure regulating heads, indicated at 42and t3, respectively, these heads being employed on the valves for thepurpose of providing adjustment for the pressures of the pilot and theprimary fluids delivered by the pumps I'I and I8, respectively, to thesystem. Beyond the pressure regulating valve 34, the primary fluid forthe system is delivered by a supply conduit 44 to pressure ports 4e andV41 oi solenoid actuated valves 48 and 49, respectively. The primaryiiuid for the system is also delivered to a port 5I of a solenoidactuated valve 52 by a vsupply conduit, indicated at 53, which connectsthe pressure port 5I with a service port 51% of the solenoid actuatedvalve 43. The solenoid actuated valves @33, 4S and 52, in the structureillustrated, are known in the trade as Vickers Solenoid Actuated ControlValves, being specified as CK-ziz-li-AC-SC, CK2164110ACSC andCK-2162-1l0-AC-SC valves, respectively. These valves are oi the sametype, the diierence in specifications being employed merely to identiiydiierences in the way the valves are assembled to obtain variations innormal operative positions.

The valves d8, 45 and 52 have return ports, respectively, indicated at56, 51 and 5B, which are connected by a return manifold or conduit 5S toreturn conduit 35, for the purpose of returning to the tank I2 theprimary iiuid supplied by the system to the various work-performingelements and after these elements have been actuated by the primary duidin the performance of useful work.

For operating the solenoid actuated valves, the valve 52 is providedwith a solenoid 5I, the valve i5 with solenoids S2 and 53, the valve 49with solenoids 54 and 55. These solenoids are elec trically connected inthe electrical control system illustrated in Fig. 5, to be hereinafterdescribed. Valves indicated at 51 are provided at each end of the valves4B, 49 and 52, actuated by the associated solenoids for controlling thepilot fluid which shifts the valves 48, 4S and 52 in response to theoperation of the solenoids 5I, 52, 53, 54 and 65.

Valves 61 are each connected to a pilot fluid supply manifold orconduit, indicated at 58, which in turn is connected to the pilot fluidsupply conduit, indicated at 23, the pressure in which is controlledthrough the pressure regulating valve 33. The valves 61 are alsoconnected to a pilot fluid vreturn manifold or conduit, indicated at B9,which communicates with the interior of the tank I2. Each of thesolenoid actuated valves 48, 49 and 52 is provided with a pair ofservice ports adapted to supply or receive primary fluid used foractuating the work-performing elements operated by the system. Forexample, the valve 49 has service ports II and 'I2 to which serviceconnections 'i3 and I4 are respectively connected, as illustrated inFig. l, the port 13 being blocked in the structure illustrated in Fig.4. The valve 48 has service ports 54 and 16 to which service conduits 53and 'I are respectively connected; and valve 52 has service ports I8 andI9 to which service connections Si and 82 are respectively connected.The service connection 82 connected with port 'I9 of valve 52 at itsopposite end is connected to a supply port 84 of a selector valve 85.The valve 85l is employed as is hereinafter described for supplyinghydraulic iiuidat primary pressure or at a relatively higher orsecondary tweemaal `cpxvcssuxze;toi.thetwonkperformingffunits"ortcylincd'ersfaoperatedrrbytthefsystem.xiIPhe selector valve 86 is described in detail in thecopendingeapplca-Iation 1: of wOtto L'Mueller, Serial No. 134,438, "led December,22,1949.

I'llhe. service connection 8 I 1 leading rfromifsup- .fs plyportl 'It ofvalve 52- likewise;communicatesfwith :rlnlett ports .81;offv ahydraulic.fluid: boosterco'f the @reciprocating Afor .rotatory type, indicatedgenfrerallyi ata, 88. .The high `pressure outlet *port @39 itheboosteri:ini turn 3f xommunicates,` through l.:arseryice:Lconduitl` 9 I iwith anl inlet porte 92Y oi` the ytselectorivalvexr B: previous-ly.referredz'to. .An outv'l lportif. leading."from-'selector'-valvcixSitcomfumunicates vwith service .conduit SSdwhich u is radapted ito supply, hydraulic .fluid to mths `work-`erformingi` elements :operated by the*4 system at itheriprimarysonseoonclaryspressures?.as will. .fbe ihereinafter described. 'Elieselector valve 86 :also has ia :portsv indicated -z'at SS communicatingrwith fiazbranchrofiservice conduit ,V8 Ifwhichzis `adapted toa supply`primaryfluidflioroperatingnthe .selecftorxvalve-B Lin `responsetol'the. operationcofxconiti'olwalve 52. 4f-Another`inletzlport,:mdicatediat 91, also communicates lipidi supply conduiti611, .for sunplyir-igil pilotiluid i for operating: selector siralverl:as will* #be here- .finafter described `Ins;the@structure.` disclosed.byf Figs. ,1.1, x23 andi, tthefboosten 88; comprises a .pair ofsboosterunits `zzzirrdicated 'byzthe numerals :98 and neil. These ,li-boosterLimits,1 which carev connected in multiple to #izoperate zas a single i.booster mechanism 1 or lipumpare ,of-fastyperknown in ithe' trade rasfrdif fi-:ferentiallpiston.rbooster units Tand `may be,purixchasediunder the .fname .Racine fbocsters. As f-fldisclosede inyFig. 4. the abooster 1 83 :comprises a rotary` pumping inuit,Laindicatedrat 1 I-Il I :adapted tto'` bexdriven:through,Laszshaft- IGZ:byte- `pilot lfluid f-actuatedfi fluidvmoton indicated ati 1:93. .Thepilot fluid for operating fluid motor H33 isfsuppliedihy tafvalve i164havingA aniinletfport vindicated yat -1 I 35 which communicates with;pilot ,luidr supply conywduit. .Atvonefend thef'valve IM communicates@-Witha branchfof `service'conduit'sli I' forisupplying primary iiuidfori-actuating tlle'valvefIM. in :one

.fdirection Theivalve isy operated ini! the opposite :directionkby 51aspring Whenfizthei-Lsupply .frompthe ...conduit 8 I `is cutf, 01T. #Afvdrainfcondut r. I III relieves pressure from ij anyiiinidigcollectingiat the r aspiring-end ofethevalve. -Thegspilot flui'drsupplied to valve1 IM through port HIE ,sis deliveredfrom Si the .valve by `way iof" one:or the. other 4oix the; ports Itor H39. .i in;normal,` position,-Atheg,` uidwis gdeliveredironi .the i port lilo-land fwheniuidfipres-Vsure is; applied toftheend by the nuidjsupplyoonduits V8 I fluid isdelivered-l from `the porty m8. :The "gportllfllfrcommunicatesi.withraconduit. I Iv I ,Which supplies fluid. tothe'rlud; 4motor` I for A,operatfiinghthe motor. An exhaust orreturnconduit I I2 returnstothe tank-I fthe .expended 'duid .which "hasbeen used in=.ope1'ating-theimotor H33. The Vdraincon'duit I I EI is ialsofoonnecteditostank` for draining `off anyA fluid which mayaccumulate, in .fthe 'E pump. f y"The, port H19. leading from i the4:valve I (i4. `like- 1Vwiselis` connected by a conduit i I I3 to i. theinlet port I I4 .cfa .springoiset solenoid actuated valve `,`II`6."Aslenoid I I I and, a` spring` are: adapted tooperate the valve` I ISbetweenpositions whereinlthe "iluid admitted .to vthe ivalvaat, port IId 1W`i1l" befdischarged. from the .valve through oneortheothenof,portsim or I I9. 'The-portello Farida I lgarei'adapted' todeliver `this ilui'd'fthizough either vof two service.conduitsdndicatedxat l. I2 I with a branch 'ffofpilot @landtI-22,rrespectively. TheaIVea lf IIi-:alsoiispror vided vwith :anexhaust-,eport r I;23 ccommunioating withexhaust'conduit I,:24:throughiwhichuidis returned; to.tank i I12 fromu oneror.`thecotheraports l* I It or IIS. yA .conduit 1 IZIJ is lcomiectedf:tofthettankfor bleeding lcfr any :ilui'd Whichrmayrcollect Withinthe `spring`endfofthevalve.

application :of the-power uniti' i110 Figi 4,? illustrates how theun'itmay beconnected to aaf'plu- I u ralityl of workir1gicylindersror`worin-.performing `:elementsppreviously; indicated by thenumerah I I.One 2 of ithese working @cylinders 1 or `a -group .fof such fworkingfcylinders: is fdesignatedf byl'the-:nufimeral IZiandlis adaptedltoperformrworlcsuchl-as might be `done -inizejecting c an c automobileiframe sill, side member or other worker workpiece from ifa'rivetingorpiercing machine ior the like. .When .i the piston r |21andfthef-oylinder,` |28 of theffwork- .i ingscylndern I2 61 :aref linthe position.illustratdn r-Figml, lworkpmay" be inserted 4 ini:theimachinetso that vthe;:operationsof the :machine ma'ycbe.pernl.formed thereon. The :piston I2I isiretainedrat fthe bottomofthe-cylinder; lxbypilotuid passing through the valveV II'Iigfromgport.. I I41to..port I I8, thence=,through.condu`it I2 I' whenthe valve is :ini -springffshifted position. In :such ,position1 `thehead: endfoi thcccylinder i I28. communicates `lwith ,the-tank; I 2through conduits I122-fand|`2ll andthe' respective Valverports IIil and'I23. `When the solenoid s I I l is energized, Pas'fwillibe! fhereinafter`r`described,r thewalve i I IS will: shiftwso nthat `port IMI will'communicate -with port .-I ITS iffor supplying pilotud to:therheadtendfoifthe cylindder `.through conduit I22,1and.porti I23 'willcom- :..muncatef with' port I I3, thereby. connectingfthe rod end of thecylinder to theitanki I2through I: conduits lf2 I and I 24. lfSuchIaireversal '.fof :pilot iiu-id inthe Aworking,zcylinden `I26 movesitthepiston .L21 to thegupperzend off.the-'cylinderf` 126,? thereupon "ejecting the :worlrfrom vthermachine.

Another-.ici therworking'cylnders IIiporarow or Vgroup of such-Working;cylinders;isiindicated -at H29. .This Work-performing; cylinderisdisposdiverticaflly inrposition to `piercefor rivet in a'vertical direction.`The fworlsing cylinder l I 2Q l comprises a,piston I3 I randafcylinder? m2,?theliea'd` endhof i the cylinder-i being inAlopensconnnunication with delivery `portrf r of selector valvesillrlthroughrconduit- 94# the` :piston rodfendbeingifinlfcominunicae .-tionwith port #It .of` control l`valve 14o :through supplytconduitill.`illustrated iinfxliig.` 4,the :'working cylinder i225`'.insaipositionitoreceive ywork. into the :machine to be later 'clampedand g;punchedLonriveted ,1,3 HAfter" the lworlohas vbeen; inserted 'finttl-1e 1 `nia- Vchine andthemotor energized, the `fluid from-the pumpwill :rbe rdischarged f to 2. tank through the open-@centeruspoolevolve! lit. When @tha-solenoid isigencrgiaemthefpilotiiuid Twillshii'ttlie spool Ato: connectyfportf54l wthpressure. port I of: valveH52., fromgportf "I9 to supply liner??` intoport Mieiselector-,valve-313. 'Fluid from Vthe selector valve .will pass.therefromtout of portfi. throughf'c'onfduitI IM; into theY head1 endsof "-alllofuthecylinders 1 `I Eiland: IM. when` 'the solenoidlrliifisienergizedgi't .wilLalso-connect; portfi withport oof valve 63,permitting-.the cylinders IZ'el to discharge Loikfrom the rod`encl-.tl'1rough yconduit Ill through Valve :.48 into lathe i return i.line, i therefore permitting itlue m vertical cylinders to ymore f intoposition and clamping .the work firmlyi in; place.

After the cylinders are i .ini` the position,LA limit .switches 22 Iywill f be actuated, completing the circuitthrouglrytheconti-.ol."panelcandenergizing l solenoid `ii toiarvalveifll,.-causing=.'the;. pilot/iuidfito shift the valve. When the valve isshifted, the port 12 is connected with port 5'1, permitting uid at therod end of the cylinders |34 to return to tank, whereupon the cylindersmove into workengaging position. At this time, limit switch 223 will beactuated through the control panel for energizing solenoid 6| of valve52 for causing the pilot fluid to shift the valve and connect ports and18 for supplying iiuid to the conduit 8|. The conduit 8| shown in fullline supplies fluid to the booster 38 and through the conduit portionsconnected thereto, shown in dotted line, supplies fluid to the port 96of the selector valve 86 and also to the valve |04. The dotted lineshowing of the conduit traces the ow of fluid when employed to shift thevalves 86 and |04.

The valve |04 is shifted by the fluid delivered in the dotted conduitportion 8| to supply pilot fluid from the port |08 through the conduitand is delivered to the uid motor |03 for driving the pintle valve ofthe booster. The pintle valve delivers fluid to a plurality ofhydraulically actuated differential pistons to produce an increase inpressure on the fluid delivered from the conduit 8| shown in solid line,which high pressure fluid isdelivered from port 89 through conduit 9| toport 92 of the selector valve 86. The primary fluid delivered throughthe port 96 of the selector valve 88 from the portion of the dottedconduit 8| connected thereto causes the valve to shift and to connectthe port 92 to the port 93 which communicates with the conduit 94. Thishigh pressure fluid enters the head end of all of the cylinders |29 and|33, producing the required work-performing operations for which eachcylinder was intended.

After a predetermined time, the solenoid 6| of valve 52, the solenoid 62of valve 48, and the solenoid 64 of valve 49 are de-energized.Simultaneously, solenoid 63 of valve 48 and solenoid 66 of valve 49 arebeing energized. The spool in valve 52 returns to its initial position,cutting off the fluid supply to the valve |04 and to the port 96 of theselector valve 86, and the iiuid in all of the conduit portions 3| isconnected to tank. The spool of the valve 86 is shifted to its initialposition under the influence of the pilot pressure applied to the port91 thereof. Simultaneously, fluid from the port 84 of the selector valveis connected through conduit 82 to the port 19 of valve 52 from which itpasses from port 58 to tank.

Upon the energzation of the solenoids 63 and 66, the pilot pressurefluid shifts the associated valves to connect port 46 to. port 16 ofvalve 48 from which fluid will pass into conduit 11 to the rod end ofcylinders |29 and connecting port 41 to port 12 of valve 49 from whichfluid will pass into kconduit 14 to the rod end of cylinders |33. Thispressure on the cylinders |29 and |33 forces the .pistons at the headend of the cylinders'to return to their original positions,exhausting'the fluidv at the head ends through the conduit 94', throughthe selector valve 86, through the conduit 82 to the valve 52 from whichit is exhausted to tank. Thereafter, limit switch 229 is actuated toenergize a magnetic timer for energizing the solenoid ||1 of thespring-loaded valve ||6. The energization of the solenoid shifts thevalve I |6, causing pilot pressure to flow to the head end of thecylinders |26 for operating the ejector mechanism for the work which isretained in operating position for a predetermined time, controlled bythe relay. Thereafter, upon the de-energization of the relay, thesolenoid I1 is ole-energized, permitting the valve to return to itsinitial position,

thereby reversing the flow of fluid on the-piston and returning thepiston and ejector mechanism to its initial position.

While the above description applies to the use of a rotary booster 88which is driven by a fluidactuated motor, the reciprocating type ofboosters 98 and 99 illustrated in Figs. 1 and 2 will operate in the samemanner to produce the increase in pressure. In such instances, the valve|04 is deleted since the conduit 8| is connected directly to theboosters to procure their operation, since the motor in this type ofbooster is not required for shifting a valve. In this arrangement, thesolenoid actuated valve ||6 is connected directly to the pilot fluidsupply conduit 23 without passing through any valve such as thatindicated at |04 in Fig. 4. It will be apparent from examining the twosystems that one type of booster is merely the mechanical equivalent ofthe other and that there is no essential difference in the power unitregardless of which type of booster may be utilized. There is likewiseno difference in the operation of the hydraulic system or of theelectrical control system therefor, as will be hereinafter apparent.

Referring now to Fig. 5, numeral I 4| indicates generally an electricalcontrol system which may be employed in operating the power unitstructure illustrated by Figs. 1 to 4. The system comprises athree-phase power line |42 consisting of conductors |43, |44 and |46passing through a switch |4l and fuses |48 to the motor |3. A conductor|49 connects a primary coil |5| of a transformer |52 across theconductors |43 and |46 of the power line |42. A conductor |53 likewiseconnects the secondary coil |54 of transformer |52 through fusesindicated at |56 to the opposite ends of conductors |51 and |58. Theseconductors provide a pair of parallel 1l'0-volt circuits for theelectrical system energized by the transformer |52.

Aplurality of conductors |59, |6|, |62, |63, |64 and |66 havingconnected therein relays |61, |68, |69, |12, I1| and |13, respectively,are connected in parallel and included Within the circuit |51. Also,another plurality of conductors |14, |16, |11, |18, |19 and |8| andincluding therein the coils of solenoids ||1, 62, 64, 6|, 63 and 66,respectively, are connected in parallel and included within the circuit|58.

The relay |61 controls a plurality of pairs of normally open contacts|610 inserted in the conductors |43, |44 and |46 of the power line |42for supplying electrical current to the motor |3. These contacts areadapted to be closed by switch bars operated by the relay |61 forclosing the circuits through the contacts when the relay |61 isenergized. Also, in a shunt circuit |82, around a manually controlledstarting switch |83 provided across the circuit |51, is another pair ofcontacts |610, having a'switch bar adapted to be closed by theenergization of the relay |61.

` The relay |68 controls a pair of normally open contacts |680 which areprovided in a shunt conductor |84 which extends around a manuallycontrolled switch |86 provided in conductor |6| supplying currentto `therelay |68. Another pair of contacts |680 is provided in the conductor|16 supplying currenty to the solenoid 62. The relay |68 closes thecontacts |688 when the coil ofthe relay is energized. Relay |69 isadapted when energized to close a pair of contacts |690 inserted in theconductor |11 supplying current to the solenoid 6:4.v "t y The relay |1|controls a pair of normally closed acca-sar contacts I1 I Ih'in'theconductorl 62supplyin'g curi rent totherelay IBSQapair ofnormally lopen contacts I'I 'l l) in a *shunt circuit |81 around almanu-` tacts I7I| in the conductor 1li-supplying current' tothe solenoid62, a pair of contacts I inthef condctor |16 supplying current to` the`solenoid 6|; a pair of contacts llllrinconductor |19 supplying currentto `the solenoid 63 and a" pair' of f'contacts- I1 I il in conductorl i21| i supplying current to the solenoid 66. The contacts l1 are `openedand the contacts' I 1 Iii-are closed when |13-are `of thetmeecontrolledrelay type.'

Thetime relay'l 12 `controls a pair of `normally openlcontacts |120Aacross conductor#18"supplyingcurrent to the solenoid '6| and a pair o1"nor mally closedcontacts '112| across the'fconductor' llsuppjlyingcurrent to' the-relay' |1|. When the relay |12 isvenergfized,y thecontacts' |120 aredrn` mediately` closed andthe contacts IlZIareimmediatel-y open; and after a period `ofti1r1e"for" Whi'c'litherrelayis set,` the contacts returnto" their'initialpositions.

The relaylll?. has aipairlof normally open contacts |130f`acrosstheconductorl 14 providing cur-`v rent for th'e solenoid'` I I1 and apa-ir'of normally closedfconta'cts |13I in shunt |34 around: thestartingfswiteh'" |66 in the plying current to LrelayV for which-'therelayis set;

Fon-operating the `system eithercmanually or automatically or forcontrolling the system manually- Vat any f stage-i in the operation"thereof and then automatically- 'beyond such stage, ,there is provided ashunt circuit for conductor I tin" the circuitl.' A branch conductor`|8|l`fronrthe conductor |88extends around the contacts |130" therconductor( I 14'.- A'" branchv conductor |9`| from the-"conductor I 88extends around the cone tacts" |1|| and" I 686*` inv the conductor |16:A" i branch conductor |92 from tl1e"conductorr |88" extends around the`contacts I 696 in theconduce tor" |11; A branch rconductor I 93`fromthe 'cone ductor' |88-extends around the contacts |1I I and' I12|liin ythe conductor 18:" A` branch conductor I 96 from the-conductor |88rextends '-a-roundith'e contacts @'I 1 Its-'inthe conductor |19, andaJbranch conductor |$6-`fromthe conductor |88 extends shunt'vcircuit;indicated at'IS; andiclosingthef separating the bar |98 from lthe"contacts |91 and." engaging the bar2|l2 withl the'r The f systemsthereupon" will be:

circuitl 51 by contacts 2i|l` capable Tofautornatic' operations, as will`be here# inaiterdescribed.

In orderto prcvide for manual operation of VLthe system-or anypart-thereof; thereis `provided in the iconductor i de `a` pair of`contacts adapted: to;A beconductor |61: sup-- |62 in series witlithe`-`contacts `|6861" Contactsfllt areclosed upon4 the 1 energization ofrelay13 and contacts |131 are i* opened 4'by such energization'lafter la'period time V formir'rg,"v a" The 203iadapted to beaclosedubya manuallyoperable switch 264; infiftheconductor mi a pair'of contacts 206 isvclosed` by a manually operable* switch-u. bai-x 267 Y in f theconductor` |91.'A` a: pairf of contacts .2M-is adapted Stube closed'lo'y-fafmanuallyvv `cylinders |29, there is operableswitch-bar 209;inthe conductor-|93` apairOcOntaCts 2|| isadaptedto be `closedtloy` amanually; operable switch bai1` 2|2; in'ithe conductor |955.` a `pairor" `contacts 2|3 is adaptedtobe closed byamanuallyoperable switch bar214, and` in the conductorl' a contaotsZlG isi` adapted to be closed bya onanu-ally'operablev switch bar 2|?. The switcnbariilli is inechani--`callyinterlccked-with a `switch'trar 2|8 Which'. engagesa pairoffcontacts 2|| `provided in cone.

ductorr |94; when the switch bar-261 is separated" Sromthe contacts 2665When-thel contacts 206 are engaged by operation lof the `contact"b'arf201 the contacts 2id will be opened.

Bygoperating switch |96 toopenthe automaticf circuit provided byconductor |61`andv to close them-anual circuit provided byshuntconductor I tia; itl will `be possible to operate' any Vof` theele-'- ments/of` the system by manually operatingther switchesilil; 201;26%,` LN2, 2I4, 2|1 or any oiL them:

Tomalretherelayv |69 responsive totheoperation ofthe Vwol-lezing`cylinder |29 (see Fig. 4'); or to the operations of any nuinberofWorking provided a plurality' of limit switchesasindicated at 22|.Thelimit` switches `22| are positioned with respect to'. the cylinders I26 in' such Way as to `be engaged bythe piston rods I2 I thereof: whenthe rodsv are exs tended from the cylinders` tothe limitofith'eirmovement during the work-performing opera tions; TheM pairs'of-contacts ,forthe switches-'22| f are indicated at` 222' andare'inserted inA conductor" I 62 supplying current to the relay |69'.Limit vswitches 223 also are positioned with" re.- spect to`4 one or`more `horizontal cylinders, suoli4 vas that indicated iat |33:` insuch' manner as to bei engagedi by theA rods -of Working cylinders |33wherrthe rods*` are extended fromA the cylinders,"

`and'adjacent thelimit of movementthereof re'- qured for rtheperformance of the work4 required ofy the cylinders. The pairs ofcontacts Ior` switclies1223,` which'are `indicated at 224, Lare 'in-fserted` in* conductors I 63"'and |64 to providetfor the energization of"the relay |12 when the' switches areH closed afterl the operationv ofthe* cylindersfr |23;

Ashuntcircuit alsois providedat 226 between: conductors 'l 63 and l 64'leading'to relaysY I 12 and'il |11; respectively: AnotherA shuntcircuit; indi# cated at22`l, extends between conductors |64. and 66leading itosolenoids I 1 I and 13, respectively:` Inserted in 1 parallelin conductor" |66 supplying currenttorelay `I 13; is` a` plurality ofotherI limit switches having contacts 228 and: indicated` att` 229 and'positioned withAv respectto cylinders |33'.` sothat'therodsorf suchcylinders will engage them switches for maintaining a closed circuitacross .contacts 226when thepistonshave been retracted.- At all othertimes the limitswitclies 229 "will befactuated'toopenthe'circuitsbetween'V theicontacts228.'

When` assembling* the apparatuscomprising'y the hydraulic *power 'unit'I l1 embracing the' prin' ciples-` of the iinvention; it `is verydesirable 'Lthat a simplied 'and'easilyservicedand installedcon''-` duitsystem be employed'b'etween the'various ele'- ments offthe structureandfirrconnecting'tlrezunit4 to l the work-performing elements-of themachine" with4M which the unit isv to be employed, Also; I. due yto thev"high fluid pressuresVV employed inthe l conduit 'systern4 embraced inthestructure; itis" advisable" to employconduits and;v conduitlconnectionsncapable" ofoperatingundr these presssuresf Withoutdaking;It' has therefore been found advisable to employ a conduit system, suchas that disclosed in the Otto Mueller copending application, Serial No.31,955, filed June 9, 1948.

In the system or unit disclosed by Figs. 1 to 4, it will be assumed, forpurposes of illustration, that pressure regulating valves capable ofproviding a constant pilot fluid pressure of 400 pounds per square inch,as one example, and a constant primary iiuid pressure of 1000 pounds persquare inch, asanother example, have been employed. Thus, the valve 33may be adjusted in such a way as to provide a fluid pressure of 400pounds per square inch in the pilot uid supply conduit 23 and the valve34 may be adjusted to provide a primary fluid pressure of 1000 poundsper square inch in the primary iiuid supply conduit 44. Also, it isassumed that one pilot fluid pumping unit, such as that indicated at 11,will supply the volume of pilot fluid at 400 pounds per square inchrequired by the power unit, and that one or the two primary fluidpumping units, indicated at 18, will supply the volume of primary fluidat 1000 pounds per square inch to meet the maximum requirement.

Also, it will be assumed that a five to one ratio booster mechanism hasbeen employed so that the secondary pressure `of the fluid employed forpiercing 4purposes will be 5000-pounds per square inch. It is to beunderstood, however, that these pressures may be varied substantially tomeet the output requirements. As pointed out above, it is possible tooperate the system either manually or automatically throughout acomplete working cycle in the manner hereinafter described.

To operate the system, assuming the switch 141 is closed, it isnecessary first to close the switch 183 for starting the motor 13. Theinstantaneous closing of switch 133 energizes relay 161, thereby closingthe contacts 1619, for closing the shunt circuit 132 around the motorstart switch 183. Thereafter, the motor 13 will run continually foreither manual or automatic operation. A switch 231 shuts ofi the supplyof current to the motor and interrupts the iiuid supply and the supplyof power at any point in the operating cycle. To operate the systemmanually, it is necessary only to actuate the switch 199 to close thecontacts 191 and to open the contacts 201. Thereafter, .any unit of themechanism may be operated by manually actuating the switches 204, 261,2119, 212, 214 or 211. It is possible also to start the automaticoperation of the system manually and at any stage'in the cycle ofoperation of the system by closing any one of the switches 204, 291,209, 212, 214 and 211 and at the same time actuating the switch 199 toclose the contacts 201 and open contacts 196.

For fully automatic operation, assuming the switch '199 to have closedthe contacts 29|, and

vassuming the motor 13 to be running, it is necessary only to place apart or piece of work in the machine being operated and to manuallyclose the automatic start switch |86. The instantaneous closing of theswitch 186 closes the electrical circuit through relay 168, therebyclosing contacts 168D for closing the shunt circuit around start switch|86 and for closing the circuit for energizing the solenoid 62 of flowcontrol valve 48. When solenoid 62 is energized, actuating valve 61moves in response to pilot fluid pressure in pilot iiuid supply lin-e68, thereby shifting control valve 48 to connect ports 54 and 4S of-valve 48,' thereby connecting primary fluid s upply conduit 44 toconduit 53. Control valve 52 being spring offset in such position as toprovide normal communication between ports 51 and 19, it will beapparent that the primary fluid pressure in conduit 53 will beimmediately communicated to port 34 of selector valve 86 .by conduit 82.Since port`91 of selector valve 86 normally is in open communicationwith pilot fluid conduit 68 and since the effect of pilot fluid pressureupon selector Valve 36 positions the valve to provide open communicationbetween the ports 84 and 93 thereof, it will be apparent that primaryiiuid supplied by the conduit 82 will be conducted through the valve 86and to the head ends of the working cylinders 129 and 133.

Simultaneously with the movement of control valve 46 to providecommunication therein between ports 54 and 46 thereof, there is alsoprovided within the valve 48 communication between ports 56 and 16 ofvalve 48, thereby providing through conduit 11 open communicationbetween the rod end of working cylinder 129 and return fluid conduit ormanifold 59. However, since control valve 49 is a spring oset valve,similar to the spring offset valve 52, it is adapted normally to provideopen communication between ports 41 and 12 thereof, thereby supplyingprimary iiuid from supply conduit 44 to the rod end of working cylinder133, through conduit 14.

Considering the working cylinders 129 and 133, it will be apparent that.when primary fluid pressure is applied to the head ends and the rod endsof the cylinder 129 are open to tank while the rod ends of workingcylinders 133 are not, pistons 131 in working cylinders |29 will moveinto a position to perform the work operations.

When the pistons |31 and the vertical cylinders 129 have approximatelymoved to work-performing position previously referred to, the limitswitches 22| are actuated, thereby closing the contacts 222 andenergizing the relay 169. The energization of relay |39 closes contacts1690 for energizing solenoid 64 of control valve 49, therebyestablishing communication between ports 41 and 12 and openingcommunication f through the valve between ports 51 and 12 thereof. Suchcommunication will connect the rod ends of working cylinders 133 to thetank 12 through conduits 14 and 59. Pistons 136 thereupon will move towork-performing position in sequence with the movement of the cylinders129.

Upon completion of the movement of the pistons 136, limit switches 223will be engaged and actuated in such a way as to close the circuitthrough timer relay 112, thereby closing the contacts 1120 forenergizing the solenoid 61 of control valve 52. The operation ofsolenoid 61 shifts the actuating valve 61 for changing the control valve52 in such manner as to close the communication between ports 51 and 19thereof, thereafter connecting ports 51 and 18 and ports 19 and 58.Primary fluid thereupon is supplied by conduit 8| to the port 96 forshifting the selector valve 86 in such a manner as to provide directcommunication between ports 52 and 93 and for actuating the booster aspreviously described for supplying fluid at secondary or high pressurefrom the booster to the head ends of vertical and horizontal workingcylinders 129 and 133, respectively. By increasing the pressure in thehead ends of the cylinders 129 and 133 from primary to secondarypressures or according to the example given, from 1000 to 5000 poundsper square inch, the pistons 131 and 136 simultaneously perform thevertical and horizontal riveting or piercing operations upon the Work.

lWhen vthe time out, 'resultngromthe-'actuation of 'timer relay' |12,ftmecontacts |121 ldse the ei-icuit throughicond'uctor |54, therebyenergizing relay |1|, which results in the opening'ofallcontacts i'lli4and closingv allcontacts |1| ll.` Thereupon, relay 69 yiscle-energized, *soleholds 62 and 8| are deenrg-iz'`ed,-`Sollehoils` 63and" 66' aieerleigized; ahd'- the time relay |73 uis ll'g'izet Whensolenoid 6| is de-energized; communica tion immediately cut olbetweenpbts lf'ad 78 and isfestablished between ports y1Q andV "58' of valve,thereby rendering v"the booster 88 `i'noperative for 'supplyingsecondary vfluid to the head ends of Wo primary pressure to the port 96of 'the "seleclfo` valve. As the high pressure in the-'selector valve isrelieved, the pilot flu-id from the port" 91 shifts the valve to itsoriginal position; connecting `the heed 'ends ef the eyuridele te thetank lzthrough conduits 32 and 5e. The de-energization ofsolefroid 62likewise cuts `of communication between ports 6' and 54 of control valve48,; therebydiscontinuing the how of primary fluid to the presesur'eport 5| of control valve 52 through the conduit 53. Theenergizetien 'of soleneids ica and es of controlvalves 48 and lle,respectively, results in the opening of communications between ports ittand 76 41 and 12 ofthe control valves, respectively,Y hence supplyingprimary fluid to the rod ends of the working cylinders |29 and 33through conduits 11 and 1ll,"`res`pec tively. Such reversal of pressure`conditions within the cylinders |29 and liresultsV in withdrawing theWorking 'cylinder pistons, thereby removing the riveting or piercingtools `from the work and Work inthe machine.

"When the pistons |36 are completely with drawn V4within the cylinders|33, the limit switches 229 are actuated 4in such ajway as to close thecircuit through timer' relay |13, thereby closing contact `|13!) for`energizing solenoid rIl'! which actuates the valve H6 in such manner aste connect the need end of ejector e'yunder |26 with the pilot uuidsuppIy line se andthe rod end to` the `return line |24communicating`with the tank I2. The pistons 21 thereupon' are moved fromthe cylinder |25 to eject the work from the machine. When the contacts|1`3| are open throughthe operation of the time controlled re-` lay |13,the circuit established bythe conductor |51 'will be open, therebycle-energizing solenoids 1, 63 and 84 and resetting thefcontrolapparatus for the next .automatic cycle of operations. `The valve IIBisspring reset upon the de-energization of the solenoid ||1, therebyreversing theconnections to the-cylinders' '|26 and connecting the rodends of the cylinders to the pilot line 68 and the head ends to tank |2.The pistons |21 `thereupon will `be withdrawn withinthe cylinders |26for the purpose of permitting the machine to be reloaded withadditionalwork.

What is claimed is:

f1. A self-contained device for supplying hy draulic uid at a pluralityof pressures including, incombinatioma tank containing a fluid, Iapumpfor supplying -fluidfrom said tanl;,-a booster acting upon and drivenbythe iluidfrom theI pump for continuously supplying fluid at increasedpres- 'releasing the sure,anda valve through which the lfluid from' said`pump and said booster 'isdeliveredfto' perfor-m work atpumpand boosterpressures, fsaid valve being shifted'by'pump pressure.`

2. A self-containeddevice forsupplying"hydraulic ilu-id at a pluralityoffpnessuresincluding;`

rking Cylinders |29 vaild |33 and A tti "13: "self-contained P device-for delivering "uid uera i plurality of pressures including, in-oor'nhinatien, a tank containing a uid, fa'-luiotoi-,Gy a pump'drivenhy fsaid motor vfor supplying-Huid at normal pressure,lasupply?offluidatsa' pressure lower-than `nor-mal` 'pressuref a booster-iforfincreasing fthe p'ressurefoi normal `fluid to `supply fluidat highpressure,- a selector valvefordsel'ectively delivering fluidf at normalandv'atf-:hi'gh pressures, Hcontrol valves for directing-the owoffn'or'mal fluid through said selector valve'-to perform Work, toreturn uid to the tankyto direct lfluid to the boosteriand to'oneendfoflthe selector valve for operating theflatter to-aposition tofpass'luid at high pressure, means fto freturn the selector valveto itsinitial position when thetfluid delivered to said one end 'thereofisdi-i rected to tank, and means veffective Whensaid iiuid -is directedtotank torelievelthe high pressure remaining in the selector valve, thereliefof which renderssaid rst means eiective to `return the selectorvalve to its initial position.

4. A self-contained device for deliverihgluid under a pluralityofpressures including, in "combinatiorr a tank containing `a uid, amotor,l La

pair of `pumps driven bysaid motor one for supplying iiuid `at normalpressure and the 'other for supplyingfluid at low pressure,afbooster'Tor increasing the pressure of normal iiuidv to supplyr uidvathigh pressure, a `selector'valve for selectively delivering yfluid atnormal and hat high pressures; and control valves for directing theoWJof n'ormal fluid 'through vsaid selector :valve to perform work, toreturn uid to thetank;v "to direct huid lto the booster and to theselector valve Afor operating `the latter to pass fluid "at highfpressure, said loW pressure-fluid operating saidcontrol valves `andreturning the selector val-ve to its 4initial position when the fluidunder normal pressure which operated the selector valveiis relievedtherefrom. l l5. :LA selfecontained A 'device for delivering `iluidundera plurality of pressures includngincomhin'ation, a tank containinga fluidffa rnotor, va pair `of pumps driven .by said motor oneiforsupplyingruidat normal pressure and the ot-lier'ior supplying `iluid atlow pressure, `a booster for' 1increasing Uthepressure of normal fluidto supply fluidl at `high pressure, a selector .valve forA selectivelydelivering "fluid `at normal 'and athigh pressur'es, control valves fordirecting. the` flo'woi vriorm'aldiuid through said selectorvalve toperform work, vto return fluid to the tank, `to direct fluid tothelbooster and to the selector valve .for op-v erating the latter topass fluid at high pressure, said Elow pressure `fluid operating saidcontrol valves and returning the selector valve toits initial positionwhen fthe ifluidfunder normalpressure which operated the selector valveis relieved therefrom, and solenoid means for operating the low pressurefluid supply to said oontrol valves.

6. A self-contained device for delivering fluid under a plurality ofpressures including, in combination, a tank containing a fluid, a motor,a pair of pumps driven by said motor one for supplying fluid at normalpressure and the other for supplying fluid at low pressure, a boosterfor in creasing the pressure of normal fluid to supply fluid at highpressure, a selector valve for selectively delivering fluid at normaland at high pressures, control valves for directing theflow of normalfluid through said selector valve to perform work, to return fluid tothe tank, to direct fluid to the booster and to the selector valve foroperating the latter to pass fluid at `high pressures, said low pressurefluid operating said control valves and returning the selector valve toits initial position when the fluid under normal pressure which operatedthe selector valve is relieved therefrom, solenoid means for operatingthe low-pressure fluid supply to said control valves, and an electricalcontrol circuit for operating said solenoid means.

'7. A self-contained device for supplying fluid under a plurality ofpressures including, in combination, a tank, a panel on said tank, amotor on said tank, a pump on said tank driven by said motor forproducing a flow of fluid at normal pressure, a supply of fluid at apressure lower than said normal pressure delivered to said panel, abooster on said panel operated by said iluid at normal pressure forcontinuously deliverz ing fluid at high pressure, a selector valve onsaid panel shiftable to supply fluid at normal and high pressures duringthe absence of high pressure in the valve, and control valves on saidpanel for controlling the supply of fluid at normal pressure to and fromone end of said se-y lector valve for controlling its operation in theabsence of high pressure in the selector valve.

8. In a self-contained device for supplying fluid at low pressure,medium working pressure and high pressure including, in combination, atank, amotor on said tank, a pump driven by said motor for producing aflow of fluid at medium pressure, means providing a flow of fluid at apressure lower than said medium pressure, z

and a booster operated by fluid at medium pressure for raising a portionof the fluid at medium pressure to high pressure and for continuouslydelivering fluid at high pressure, said motor, pump and booster beingsupported by said tank.

9. In a self-contained device for supplying fluid at low pressure,medium working pressure and high pressure including, in combination, atank, a motor on said tank, a pump driven by said motor for producing aflow of fluid at medium pressure, means providing a flow of fluid at apressure less than said medium pressure, a booster operated by fluid atmedium pressure for raising a portion of the fluid at medium pressure tohigh pressure and for continuously delivering fluid at high pressure,said motor, pumps and booster being supported by said tank, a panelsupported by said tank, and a selector valve supported on said panelthrough which fluid at medium and high pressures is selectivelyconducted through the shifting oi said valve by fluid at a pressure lessthan high pressure.

l0. In a self-contained device for supplying fluid at low pressure,medium working pressure and high pressure including, in combination, a

i6 tank, a motor on said tank, a pair of pumps driven by said motor oneproducing a flow of fluid at low pressure and the other producing a flowof fluid at medium pressure, a booster operated by fluid at mediumpressure for raising a portion of the fluid at medium pressure to highpressure, said motor, pumps and booster being supported by said tank, apanel supported by said tank, a selector valve supported on said panelthrough which fluid at medium and high pressures is selectivelyconducted, said selector valve containing a spool shiftable lengthwise,a supply conduit from said medium pressure supply `connected to one endof said selector valve for shifting the spool for changing the deliveredfluid from medium to high pressure, and a conduit connected from the lowpressure supply to the opposite end of the valve for returning saidspool to initial position automatically when the supply of fluid atmedium pressure ls cut off from said one end.

1l. In a selfcontained device for supplying fluid at low pressure,medium working pressure and high pressure including, in combination, atank, a motor on said tank, a pair of pumps driven by said motor oneproducing a flow of fluid at low pressure and the other producing a flowof fluid at medium pressure, a booster operated by fluid at mediumpressure for raising a portion of the fluid at medium pressure to highpressure, said motor, pumps and booster being supported by said tank, apanel supported by said tank, a selector valve supported on said panelthrough which fluid at medium and high pressures is selectivelyconducted, said selector valve containing a spool shiftable lengthwise,a supply 'conduit from said medium pressure supply connected to one endof said selector valve for shifting the spool for changing the deliveredfluid from medium `to high pressure, a conduit oonnected from the lowpressure supply to the opposite end of the valve for returning saidspool to initial position automatically when the supply of fluid atmedium pressure is cut off from said one end, said panel havingapertures therethrough for the passage of the fluid at medium and lowpressures to the ends of the valve forA shifting the valve spool, saidpanel also having an aperture through which fluid at medium and highpressure is delivered from the valve, said panel also having a pair ofapertures therethrough one for delivering fluid at medium pressure andthe other for delivering fluid at high pressure to said valve, and meansfor securing the selector valve to the face of said panel with theapertures of the valve aligned with the apertures through the panel andsealed thereto.

l2. In a self-contained device for supplying fluid at low pressure,medium working pressure and high pressure including, in combination, a

tank, a motor on said tank, a pair of pumps driven by said motor oneproducing a flow of fluid at low pressure and the other producing a flowof fluid at medium pressure, a booster operated by fluid at mediumpressure for raising a portion of the fluid at medium pressure to highpressure, said motor, pumps and booster being supported by said tank, apanel supported by said tank, a selector valve supported on said panelthrough which fluid at medium and high pressures is selectivelyconducted, said selector valve containing a spool shiftable lengthwise,a supply conduit from said medium pressure supply connected to one endof said seleotorvalve for shifting the spool for changing the deliveredfluid from medium to high pressure, a conduit connected Vfrom the lowpressure supply to the opposite end of the valve for returning saidspool to initial position automatically when the supply of iluid atmedium pressure is cut o from said one end, said panel having aperturestherethrough for the passage of the fluid at medium and low pressures tothe ends of the valve for shifting the valve spool, said panel alsohaving an aperture through which fluid at medium and high pressure isdelivered from the valve, said panel also having e, pair of aperturestherethrough one for delivering fluid at medium pressure and the otherfor delivering fluid at high pressure to said valve, and meansforsecuring the selector valve to the face of said panel with the aperturesof the valve aligned with the aperturesthrough the panel and sealedthereto, said seal for the apertures conducting fluid at low and mediumpressures for shifting the spool being sealed by O-rings, the aperturesfor delivering fluid at normal and high pressures to and from the valvebeing sealed by metal sleeves which are urged into sealed relation bythe pressure of the fluid passing through said sleeves.

13. In a self-contained device for supplying uid at low pressure, mediumworking pressure and high pressure including, in combination, a tank, amotor on said tank, a pair of pumps driven by said motor one producing ailow of fluid at low pressure and the other producing a flow of fluid atmedium pressure, a booster operated by iiuid at medium pressure forraising a portion of the fluid at medium pressure to high pressure, saidmotor, pumps and booster being Asupported by said tank, a panelsupported by said tank, a selector valve supported on said panel throughwhich iluid at medium and high pressures is selectively conducted, saidbooster also being secured to said panel, control valves secured to saidpanel shiftable by iluid delivered at low pressure, conduits connectingthe low pressure supply of iiuid to said control valves and one end ofsaid selector valve and the medium pressure supply of fluid to saidvalves, to said booster, to said selector valve and to said tank,pressure regulating valves in the delivery conduit of said pumps bywhich the flow of iiuid at low and medium pressures delivered therebymay be adjusted, solenoid actuated valves on said panel for controllingthe flow of low pressure fluid to said control valves, and a secondpanel on said tank containing an electric circuit for controlling thesequential actuation of the solenoid valves to regulate the ilow of thefluid relative to the work to be performed.

14. A self-contained device for supplying fluid at a plurality ofpressures, a tank for holding the fluid forming the base of the device,a motor and a pair of pumps mounted on said tank for deliverng fluidfrom one pump at low pressure and from the other pump at normal workingpressure, a panel supported by said tank, a booster on said paneloperated by fluid at normal pressure for delivering iiuid at highpressure whereby to provide a self-contained unit delivering iluid atthree pressures, and a selector valve for controlling the delivery ofiiuid at normal and at high pressures shifted by said normal pressurewhen said booster is operated at normal pressure for delivering iluid athigh pressure, said low pressure fluid shifting said selector valve toinitial position for delivering fluid at normal pressure when said iluidat normal pressure which shifted the valve is cut off therefrom.

15. A self-contained device for supplying fluid 4at a plurality ofpressures, a tank for holding the iluid formingthe base of the device, amotor and a pair of pumps mounted on said tank for delivering fluid fromone pump at low pressure and from the other pump at normal workingpressure, a panel supported by said tank, a booster on said paneloperated by fluid at normal pressure for delivering fluid at highpressure whereby to provide a self-contained unit delivering fluid atthree pressures, a selector valve for controlling the delivery of fluidat normal and at high pressures shifted by said normal pressure whensaid booster is operated at normal pressure for delivering fluid at highpressure, said low pressure fluid shifting said selector valve toinitial position for delivering uid at normal pressure when said uid atnormal pressure which shifted the valve is cut olf therefrom, a panel onsaid tank for supporting said booster and selector valve, a plurality ofcontrol valves on said panel actuated by iluid at low pressure forcontrolling the flow of normal uid to the booster, the selector valve,to tank and to conduits which supply iiuid to work-performing elementsseparate from the device, and solenoid means for controlling the supplyof fluid at 10W pressure to said control valves.

16. A self-contained device for suppllyingiluid at a plurality ofpressures, a tank for holding the fluid forming the base of the device,a motor and a pair of pumps mounted on said tank for delivering fluidfrom one pump at low pressure and from the other pump at normal Workingpressure, a panel supported by said tank, a booster on said paneloperated by fluid at normal pressure for delivering fluid at highpressure whereby to provide a self-contained unit delivering fluid atthree pressures, a selector valve for controlling the delivery of fluidat normal and at high pressures shifted by said normal pressure whensaid booster is operated at normal pressure for deliv- .ering fluid athigh pressure, said low pressure fluid shifting said selector valve toinitial position for delivering iiuid at normal pressure when said fluidat normal pressure which shifted the valve is cut off therefrom, a panelon said tank for supporting said booster and selector valve, a pluralityof control valves on said panel actuated by iluid at low pressure forcontrolling the flow of normal fluid to the booster, the selector valve,to tank and to conduits which supply fluid to work-performing elementsseparate from the device, solenoid means for controlling the supply offluid at low pressure to said control valves, and conduitsinterconnecting said valves, booster and pump and providing terminalends for the delivery and return to tank of fluid under normal pressureand fluid under normal and at high pressures, said terminal endsproviding connecting means by which the conduits from workperformingelements are conductively joined to said device.

17. A self-contained device for supplying iluid at a plurality ofpressures, a tank for holding the fluid forming the base of the device,a motor and a pair of pumps mounted on said tank for delivering fluidfrom one pump at low pressure and from the other pump at normal workingpressure, a panel supported by said tank, a booster on said paneloperated by fluid at normal pressure for delivering fluid at highpressure whereby to provide a self-contained unit delivering iluid atthree pressures, a selector valve for controlling the delivery of fluidat normal and at high pressures shifted by said normal pressure whensaid booster is operated at normal pressure for delivjpump and providingterminal -ends Afor livery sand return `vin'glluidat low 4and "taining'sa-id `iluid, va

lector valve through which the u'id at low '19 fer-ing u'id at 'highpressure, said `alow pressure iluid shifting said selector val-ve .to-initia'l Apositionlfor delivering lfluid at normalpressure-W-hen 1saidfluid at normal pressure which Alshifted 'the valve is cutoi therefrom,a panel `on said tank ytor-supporting said booster and selector valve, a

plurality of ycontrol valves -on said panel yactu- 'fated fby iiuid latlow lpressure vfor controlling vthe `110W of normal 4-iiuid Ato thebooster, the selector 'valvejto tank/and Etoconduits whichisupply fluid"to iWork-performing `elements separate vfrom the device, solenoid means'forcontrolling the supply :of lfluidaltlowpressure'to Asaid controlvalves, and 'conduits interconnecting said valves, "booster and the-deto ltank of ffluid under ynormal xpressure and iluid under normal and:at high "pressures, and `to deliver'andreturn to 'tank Ailuicl "atlowpressure.

A18. In ya self-contained power `unit ffor deliverat high pressure, atank conmotor, fra *pump Joperated fby said motor `Tor producing aV'iiow "of -fluid Vatt low lpressure, a'booster operated 'by said fluidfor producing a 'flow of fluid 'at high pressure continuously as long asthe booster .is operated, a seand 1high,pressures islselectivelydelivered, means for Ashift-,ing-said valve .to high pressuredeliveringpo- .'-sition, and means for shiftingsaid valve back to .lowpressure delivering position rendered effecltive when thehighgpressurein the valve has been relieved.

,19. :Inaselfcontainedfpower unltffor deliverl,

inglflui'd at low'and at fhigh pressure, a .tank containing -saidifluid, a motor, `a :pump loperated :by said motor for producing a 110W.of `fluid vat low pressure, afbooster operatedlbyfsaidfvfluidlforpro-Atlucing la lLflovv of fluid -at lhigh pressure .continuously as 'longas the fbo'oster lis operated, aa fseulector :valve through 4which thefluid fat llow land 'high kpressures iis vselectively delivered,:meansffor fs'hifgting said valve to high pressure :deliver-inguposition tloe'forehigh pressurels delivered thereto, `and meansAeffective 1in the iabsence of said irst means and after vhigh pressureI'has been relieved .from ithe valve vto fshift said yvalve Lb'ack tolow 'pressure delivering position.

520. kA self-containeddevice f-for delivering Sfluid under i a pluralityof pressuresincludingin combination, :a itank l,containing :a iiuid, a`motorf-u --pair of pumps driven by said Lmotor :one forsulh plyingfluid fat'fnormal `.pressure .and the other fo'r 'supplying vfluid atlow pressure, fa `booster for iiny'creasing fthe :pressure 'of `normalfluid fito rsupply "fluid .at high pressure, Ea-slector "valve ffor:selectively vdelivering fluidi-at normal fand 4at :high pressures,A'control valves forfdirecting ithei'owidf normal fluid through -saidyselector `valve :to iper- 'form work, to return uid to .fthe itank, to:direct fluid 'to fthe'fboos'ter Iand to 'the Lselector val-ve forzoperating the `latter to pass uid at high pressure, and means forreturning fthe iselector valve to its initial position when the 'fluidunder :nonmal pressure which operated the .selector 1valve fisrelieVedtherefrOm.

`DTT() IMUELUER.

Vlnteferenees Cited in the fiile 'of :this patent UNITED'STATES PATENTSNumber Name Date 1,333 ,-660 yHutelflin's Man `16, 111920 1,451,303Mithell Apr. 10, "11933 2,058,377 Francis Oct. v20, 193B 2,088,859 4Huk'Aug. "f3, S1937 2,218,565 Vickers Det. 22, 19440 2,231,307 Wallace Feb.l1, 4119411 2,347,301 'Twymanlet al -Apr.'25,1944 42,355,669 Moser-Aug."15, 1944 2,366,388 "Crosby Jan. "2,5'1945 2,532,856 Ray Dec. :5,15950

